#include<stdio.h>                                                                                                             
      
int sum(int s,int e)      
{      
    int result=0;    
    
    int i=s;    
    for(;i<=e;i++)    
    {    
        result+=i;    
    }    
    return result;    
}    
    
int main()    
{    
    int start =1;    
    int end=100;    
    printf("I will begin\n");    
    int n=sum(start,end);    
    printf("running done, result is :[%d~%d]=%d\n",start,end,n);    
    return 0;    
                                                                                                                             
} 
